Imidazo[1,5-a]pyridines reported in the literature are for the most part only functionally substituted on the imidazole portion of the bicyclic ring system. For example 1- and 3-aminoalkyl substituted imidazo[1,5-a]pyridines and tetrahydro derivatives are described in Journal of Medicinal Chemistry 16, 1272-6 (1973). The synthesis of several 5-substituted imidazo [1,5-a]pyridines, e.g. 5-ethoxycarbonyl-imidazo[1,5-a]pyridine, has only been recently described in Tetrahedron letters 21, 2195-6 (1980).
Various substituted imidazoles, e.g. carboxyheptylimidazole (British patent 2,016,452) have been reported as thromboxane synthetase inhibitors.
The present invention is concerned with imidazo [1,5-a]pyridine alkanoic acids and derivatives representing a novel class of suprisingly potent and highly specific thromboxane synthetase inhibitors.
The foregoing advantages and attributes render the imidazo [1,5-a]pyridine derivatives of this invention particularly useful when administered, alone or in combination, to mammals, e.g. for the treatment or prevention of diseases responsive to the inhibition of thromboxane synthetase comprising cardiovascular disorders such as thrombosis, atherosclerosis, cerebral ischaemic attacks, myocardial infarction, angina pectoris, hypertension; respiratory disorders, such as asthma; inflammatory disorders; and migraine headache.